1. Field of the Invention
The present invention relates generally to a printing-cylinder bearing device for rotary presses, and more particularly to a blanket-cylinder and plate-cylinder bearing device that can be moved to a printing position and non-printing position.
2. Description of the Related Art
As to printing-cylinder bearing devices, one disclosed in Japanese Patent Publication No. 2533040 based on the claims of priority whose priority country is Federal Republic of Germany, and whose date and number of priority application are Aug. 10, 1991 and P4126545.9 is publicly known.
In the Japanese Patent Publication No. 2533040 disclosed is a printing cylinder bearing device for printing presses comprising an inner ring, an intermediate ring and an outer ring, all serving as a raceway, between which ball and roller rows are disposed. The inner ring of the bearing device is fitted into a journal of the printing cylinder, whereas the outer ring is fitted to a bearing casing.
The centerline of the inside diameter of the intermediate ring is aligned with the centerline of the shaft of the printing-cylinder, whereas the centerline of the outside diameter of the intermediate ring is aligned with the centerline of the bearing casing hole, and misaligned with the centerline of the inside diameter of the intermediate ring. That is, the outside diameter of the intermediate ring is eccentric to the inside diameter of the intermediate ring. The intermediate ring is caused to rotate in the circumferential direction around the centerline of the outside diameter as the fulcrum by a manipulating member disposed outside of the bearing casing. By causing the intermediate ring to rotate, the printing cylinder having the inside-diameter centerline of the intermediate ring aligned with the centerline of the shaft is also caused to move around the outside-diameter centerline of the intermediate ring.
The ball-and-roller bearing rows between the inner ring and the intermediate ring comprise cylindrical roller bearing row and ball bearing row or cross roller bearing row; the ball-and-roller bearing rows between the intermediate ring and the outer ring comprise cylindrical roller bearing row and ball bearing row.
The cylindrical roller bearing row is a bearing for supporting the radial load exerted in the radial direction of the printing cylinder, while the ball bearing row or the cross roller bearing row is a bearing for supporting the thrust loading exerted in the axial direction of the printing cylinder. If any one of these bearing rows having different actions provided side by side between the inner ring and the intermediate ring and between the intermediate ring and the outer ring is damaged, the entire assembly of the inner ring, the intermediate ring, the outer ring and the ball-and-roller bearing rows disposed there between has had to be replaced.
The inner ring of the bearing device is fitted to the journal of the printing cylinder to prevent axial movement, and the outer ring of the bearing device is fitted to a hole provided on the bearing case of the printing cylinder to prevent axial movement. The radial and thrust loadings exerted in the axial and radial directions of the printing cylinder are transmitted to the inner ring, intermediate ring and outer ring, and bearing casing of the bearing device. The cylindrical roller bearing row of the two bearing rows provided between the inner ring and the intermediate ring and between the intermediate ring and the outer ring sustains the radial load, while the ball bearing row or the cross roller bearing row sustains the thrust loading. The construction where loads are sustained by a plurality of bearing rows and a plurality of bearing-row stages in this way tends to cause large play, and the play due to thrust loading tends to be compounded due to the accumulation of plays in the bearing rows between the inner ring and the intermediate ring and between the outer ring and the intermediate ring.
A printing-cylinder bearing device where a radial bearing and a thrust bearing are independently provided, on the other hand, is disclosed in Japanese Patent Publication No. 2758346, based on the claims of priority whose priority country is Federal Republic of Germany, and whose date and number of priority are Aug. 21, 1992 and P4227643. In this bearing device, a radial bearing is provided on the shaft of the printing cylinder to sustain the radial load exerted in the radial direction of the printing cylinder, and a thrust bearing is disposed in such a manner that the printing-press frame to which the radial bearing is fitted is sandwiched on both sides by the thrust bearing to sustain the thrust loading exerted in the axial direction of the printing cylinder. This bearing device, however, is a stationary bearing which is not designed to move the printing cylinder between the printing position and the non-printing position.
It is an object of the present invention to provide a printing-cylinder bearing device which produces less plays in supporting the printing cylinder, and which assures easy maintenance since the loads exerted in the radial and axial directions of the printing cylinder are sustained by separate bearings, and any of them can be easily replaced with new one even when damaged.
It is another object of the present invention to provide a printing cylinder bearing device having an eccentric part to allow the printing cylinder to move between the printing position and the non-printing position.
It is still another object of the present invention to provide radial-load supporting means having a construction having an eccentric part that is rotated around the centerline of a hole provided on a support member and has a hole whose centerline is misaligned with the centerline of the hole provided on the support member so as to sustain the radial load acting in the radial direction of the printing cylinder.
It is a further object of the present invention to provide a bearing construction and a bearing that are suitable for carrying the radial load of the printing cylinder.
It is a still further object of the present invention to provide a printing-cylinder shaft construction and a bearing that are suitable for carrying the thrust loading acting in the axial direction of the printing cylinder.
It is a still further object of the present invention to provide means for driving an eccentric part to rotate it so that the printing cylinder can be moved between the printing position and the non-printing position.
In the disclosed embodiments, the printing-cylinder bearing device that causes the frame to support the printing cylinder in such a manner that the printing cylinder can be rotated and moved between the printing position and the non-printing position comprises radial-load supporting means at least having between the frame and the printing cylinder shaft an eccentric part that can be rotated around the centerline of a hole provided on the frame and has a hole whose centerline is misaligned with the centerline of the hole provided on the frame, a housing that interacts with the eccentric part and inhibits the axial movement of the printing cylinder with respect to the frame, thrust-loading supporting means provided in between the housing and the printing cylinder shaft, and eccentric part rotating means that causes the eccentric part to rotate around the centerline of the hole provided on the frame and holds the position.